Pint-size gym titan David Barton is leaving his eponymous line of sleek fitness studios, Page Six has learned exclusively.

The 5-foot-5, muscle-bound entrepreneur, who founded the trendy David Barton Gyms 20 years ago, notified his investors via letter Thursday he was stepping down from the business to pursue other opportunities.

“The gym has been my baby, and it’s a thrilling experience to have led a fitness revolution,” Barton told Page Six on Friday.

“I’ve left them with a great platform, and I’m sure the business will continue to thrive, but now I’m on to the next revolution.”

Barton won’t disclose what his next move is, and denies he was pushed out of the business by investors.

Barton opened his first gym in 1992 on 15th Street and Sixth Avenue with money he’d earned working as a personal trainer and kept stashed in a pillowcase.

After opening locations on the Upper East Side and in Chelsea, Barton launched a giant, 38,000- square-foot gym in the old Barnes & Noble space on Astor Place.

He reportedly spent $8 million constructing the space, which looked more like a Victorian Goth nightclub than a fitness venue. DJs would play during “gym happy hours” in a DJ booth set inside a large disco ball that once hung in a nightclub called Happy Valley.

Famous faces often found at Barton’s sleek facilities included Anderson Cooper, Rachel Weisz, Daniel Craig and Amanda Lepore.

After opening clubs in Los Angeles, Miami and Chicago, Barton filed for Chapter 11 bankruptcy in 2011, following an aggressive expansion during the recession, which left the company overextended.

He managed to restructure more than $65 million in debt and struck a partnership with California-based gym chain Meridian Sports Club.

Shortly before the bankruptcy, Barton made headlines when he split with his longtime partner, club promoter Susanne Bartsch, after 15 years of marriage. The couple have one son, Bailey.